SWODY2
SPC AC 171732
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1232 PM CDT SAT MAY 17 2008
VALID 181200Z - 191200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
COLD UPPER LOW...CURRENTLY LOCATED OVER NRN ONTARIO...WILL CONTINUE
A SEWD MOVEMENT TODAY THROUGH SUNDAY...AND SHOULD REACH THE LOWER
GREAT LAKES/NERN STATES BY 12Z MONDAY. SEVERAL JET AND ATTENDANT
VORTICITY MAXIMA WILL ROTATE THROUGH THE ERN U.S. UPPER TROUGH.
MEANWHILE...THE WRN U.S. RIDGE WILL REMAIN ANCHORED ALONG AND JUST W
OF THE CA COAST ON SUNDAY...WITH HEIGHT FALLS PERSISTING ACROSS ORE
TO WRN CANADA AS ONE PACIFIC TROUGH TOPS THE RIDGE EARLY SUNDAY AND
A STRONGER TROUGH APPROACHES BC LATE IN THE FORECAST PERIOD.
DOWNSTREAM HEIGHT RISES OVER THE SRN ROCKIES/HIGH PLAINS WILL
SUPPORT AN EWD PROGRESSION OF THE SRN HIGH PLAINS TROUGH DURING THE
DAY 1 PERIOD REACHING E TX/LOWER MS VALLEY BY 12Z SUNDAY. THIS
SYSTEM WILL WEAKEN SUNDAY AS IT MOVES THROUGH CONFLUENT FLOW REGIME
WITHIN BASE OF DEVELOPING ERN U.S. LONGWAVE TROUGH.
AT THE SURFACE...A TROUGH IN LEE OF THE ROCKIES SHOULD SHIFT EWD
INTO THE PLAINS/CANADIAN PRAIRIE SUNDAY NIGHT. MEANWHILE...A
WEAK/REINFORCING COLD FRONT IS EXPECTED TO CROSS THE APPALACHIANS BY
AFTERNOON...AND THEN CONTINUE EWD/OFF THE ATLANTIC COAST THROUGH THE
END OF THE PERIOD. WRN EXTENT OF THIS BOUNDARY WILL MOVE SWD
THROUGH THE TN VALLEY AND REACH SRN PARTS OF GA TO MS BY 12Z MONDAY.
...MID-ATLANTIC REGION WSWWD INTO NRN GA/PARTS OF NRN AL/MS...
MODELS CONTINUE TO INDICATE MINIMAL DESTABILIZATION ACROSS THE
MID-ATLANTIC REGION AND WSWWD ACROSS THE CAROLINAS INTO NRN GA.
SLIGHTLY STRONGER INSTABILITY IS POSSIBLE FARTHER W ALONG THE COLD
FRONT INTO PARTS OF NRN AL/MS WHERE MLCAPE SHOULD APPROACH 500 J/KG
GIVEN GREATER SURFACE MOISTURE THAN EXPECTED FARTHER E. FORCING FOR
ASCENT ATTENDANT TO PROGRESSIVE OH VALLEY SHORT WAVE TROUGH SHOULD
BE STRONGEST FROM PA SWD TO THE CAROLINAS... SUPPORTING SHOWERS AND
TSTMS ALONG THE FAST MOVING COLD FRONT. WEAK INSTABILITY SHOULD
LIMIT THE THREAT FOR SEVERE. HOWEVER...STRONG/GENERALLY
UNIDIRECTIONAL DEEP-LAYER WIND FIELD SUGGESTS A THREAT FOR
LOCALLY-DAMAGING WINDS DURING THE AFTERNOON...WITH ANY STRONGER LINE
SEGMENTS.
FARTHER W INTO NRN AL/MS...MODELS SUGGEST A WEAK IMPULSE WILL TRACK
SEWD INTO THE LOWER TN VALLEY REGION SUNDAY AFTERNOON SUPPORTING
CONVECTIVE DEVELOPMENT ALONG WRN EXTENT OF THE FRONT.
ALTHOUGH DEEP LAYER SHEAR IS EXPECTED TO BE WEAKER ACROSS THE LOWER
TN VALLEY THAN LOCATIONS FARTHER E...STRONGER INSTABILITY MAY OFFSET
THIS LIMITING FACTOR AND SUPPORT A FEW STRONG TO SEVERE TSTMS INTO
PARTS OF NRN MS SUNDAY AFTERNOON. THE AREA OF LOW SEVERE
PROBABILITIES HAS BEEN EXTENDED W TO INCLUDE NRN MS FOR THIS REASON
COMBINED WITH MODEL CONSENSUS INDICATING TSTM DEVELOPMENT ACROSS
THIS REGION.
...PARTS OF NRN AND CENTRAL FL...
ALTHOUGH A WARM/MOIST AIR MASS WILL EXIST ACROSS THIS REGION...
POINT FORECAST SOUNDINGS INDICATE A WARM LAYER BETWEEN 850-700 MB
WHICH MAY TEND TO LIMIT UPDRAFT ACCELERATIONS AND THE OVERALL
DEVELOPMENT OF MORE ROBUST STORMS. HOWEVER...STRONG DEEP LAYER
WESTERLIES SUGGEST THAT STRONGER CORES THAT CAN DEVELOP WILL HAVE
THE POTENTIAL TO PRODUCE BRIEF GUSTY WINDS.
..PETERS.. 05/17/2008
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@PO.UIUC.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.
No comments:
Post a Comment